When Val Schaffner installed solar panels on his East Hampton farmhouse three years ago, he thought he would be safe from the power outages that often followed destructive storms. Then came Hurricane Irene.

"We were kind of smug thinking we had solar power," he says. "But when Irene hit, we were in the dark just like everyone else."

Schaffner made sure he was ready when superstorm Sandy arrived, and the lesson he learned was one those considering solar also should take into account. Getting energy from the sun is great under most circumstances. But if you want to make solar work under all conditions, you're going to need backup.

Backup in this case means a battery bank, an addition that has both pros and cons. Yes, it adds cost to the system. And, yes, it's going to take up some space in the garage. What it does do, however, is keep your home humming along -- on a limited basis -- when the grid goes down.

For the moment, having that battery bank is unusual: Of the approximately 5,000 people who have solar systems on Long Island, officials estimate that only about three dozen have battery backup. People who have solar panels but no batteries are dependent on the grid for their electricity and therefore subject to power outages just like everyone else.

What follows are tales of three homeowners who installed battery banks, along with an explanation of how they work and information about the cost of a solar power system.

POWERING UP

William Hecker, 54, a homeowner in the Town of Hempstead (pictured to the right), was satisfied with how his system worked during the recent storm and especially likes the independence that goes along with it. "We're virtually a power plant."

He bought his system along with the battery bank four years ago and already had it hooked up to critical systems when the grid went down. This included things like the refrigerator, the freezer, ceiling fans and kitchen appliances. "We were without power for five days and had absolutely no issue with the stuff we had running on batteries," says Hecker, a retiree who worked in law enforcement.

With rebates and tax credits, he figures the system cost him about $25,000. His electric bills have dropped dramatically, enough that he figures he will recoup his capital outlay in a decade. Most earn money back in five to six years, according to solar manufacturers.

'BYE TO THE GRID

Three years ago, Helen Mecagni had 20 solar panels installed on her roof in Baiting Hollow. Last year, she added a battery pack in the garage. She even put a small solar generator in her backyard to charge an electric fence around her chicken coop (see image to the right).

"It keeps the chickens in and the cats and dogs out," she says. "It works great, except sometimes I forget and shock myself."

Her system ran about $30,000, but with the usual givebacks ended up costing about $6,000, says Mecagni, 54, a senior probation officer with Suffolk County. Why did she decide to add the battery bank?

"To be honest with you, it irritated me to be completely tied to the grid," she says. "With my battery system, LIPA could disappear off the face of the Earth, and I would still have power to run my refrigerator, freezer, computer, my fish tank, the TV, the hot water heater, a lot of lights and even a small air-conditioner."

Her electric bills are little or nothing now, she says. And Mecagni figures she will reach the payback point for her initial outlay in five to six years. As far as how the batteries performed, she actually lost power for only about 10 minutes, but everything worked fine. "It was a short-lived thrill," she says, "but it was good because it tested the system."

ELECTRIC CAR, TOO

Val Schaffner (pictured at right), who is usually in the city with his family, was disappointed when his East Hampton farmhouse went dark after Irene struck. That's why he added a battery bank last year. It worked like a charm during Sandy, but he wasn't there to see it.

"The ironic thing is that I wanted to drive out there, but I wasn't able to find gas for my car," he says. Instead, he and his wife and three children were stuck in their darkened apartment in a part of Manhattan that lost power for five days.

A 61-year-old author and essayist, Schaffner says he wants one day to be completely energy liberated. The 55 photovoltaic panels on his roof and battery bank in his garage set him back around $20,000 after the usual tax credits and rebates, he said. He recently bought an electric car, which he will charge with the system.

"I'm thrilled with my solar array," he says. "It's a good feeling to be producing as much electricity as I consume. It's pretty much eliminated my electric bill."

How does a battery bank work?

Most people these days know how solar power works. The sun's rays are collected by a photovoltaic panel made up of two layers. One layer becomes positively charged, the other negatively charged. When a wire connects the two, electricity is produced. That electricity is sent directly to LIPA, and LIPA turns around and sends electricity back to the supplier's home, adjusting the bill accordingly.

A solar battery bank meanwhile stores some of the electricity collected by the panels, and it kicks in when the grid fails. Another small device, called an inverter, changes the DC current from the panels into AC current, the kind used in homes.

The battery bank isn't to be confused with a solar generator, which is portable and independent of the grid, and can be used to run things like a TV at a campsite or power tools at a remote construction site.

Homeowners prepared for a grid power outage usually have their battery banks hooked up to a circuit to run essential items in the house when the grid fails. It switches off automatically when the grid comes back on again.

Typically, a battery bank will keep critical systems in a home running for several days -- longer if the sun comes out immediately after a storm, allowing the bank to recharge, says R. Sail Van Nostrand, who owns a Northport solar equipment firm and is president of the New York State Solar Energy Industries Association. Don't expect them to power an entire home, however. "It's an environmentally safe thing to do," says Van Nostrand, "but it's not necessarily equivalent to a gas generator."

Should you own or lease?

Homeowners who love solar but don't have the money to buy the system now, have another option -- leasing. "It's almost like a car," says Michael Deering, vice president of environmental affairs for the Long Island Power Authority, which approved this new payment method three weeks ago. "You can buy one or lease one."

With this arrangement, a solar company installs solar panels on a resident's roof for free. The company owns, maintains and insures the equipment and leases it back to the homeowner, who then gets to pay a lower rate for power.

Since the cost of producing that power goes down, so does the homeowner's bill, although they pay a part of that savings to the solar company, which is their profit. State tax credits still apply, which increases homeowner savings.

Ed Steins, Northeast regional vice president of SolarCity, says about 30 customers on Long Island have signed up since the program was approved. The company, which has regional headquarters in Hauppauge, estimates a customer could save $12,000 over the life of a 20-year lease and more with a prepaid plan. "The economics are significantly better than buying a solar system," Steins says.

How much does solar power cost?

It's free. The sun's power, that is. But you don't get the system for nothing. The good news with solar is that although there is a capital outlay, someday in the future, you actually might get your power gratis.

So, what is that price tag? Several factors come into play.

The initial cost depends on local prices for equipment, what type of photovoltaic system you want (with or without batteries) and how big a system you want. Another element is the size of your home and whether you have it outfitted with energy-draining items such as central air-conditioning and big-screen televisions. The good news is that once you add up all the costs, you get to reduce the bottom line by subtracting state and federal tax credits and LIPA rebates.

Also on the positive side, if you live in an area with plenty of sun (Long Island is well positioned to take in rays) and have an unobstructed south-facing roof as a platform for the panels, you can soak up lots of energy rays. That means you pay off the system more quickly and start saving money sooner.

R. Sail Van Nostrand, who owns a solar firm in Northport, estimates the outlay for an "average" house would be about $30,000. From this, you could subtract an $11,000 LIPA rebate and about $10,000 in state and federal tax credits, he says. So the total cost would be anywhere from $8,000 to $10,000, although the price would rise another $10,000 or so with a battery bank.

Most solar owners see their electricity bills reduced significantly. A few produce more electricity than they consume. LIPA pays the homeowner for any excess power produced at the end of each year.

"So this is buying a system that lasts for 25 years or more and getting your money back within a few years," Van Nostrand says. "And after that you're essentially not buying electricity anymore."